Semiconductor components based on nitride compound semiconductors are predominantly used in optoelectronics, in particular for generating radiation in the ultraviolet, blue and green spectral regions. In the text which follows, the term “based on nitride semiconductors” means that a component or part of a component described in this way preferably comprises InxAlyGa1−x−yN, where 0≦x≦1, 0≦y≦1 and x+y≦1. This material does not necessarily have to have a composition which is mathematically precise according to the above formula. Rather, it may include one or more dopants and additional constituents which leave the physical properties of the material substantially unchanged. For the sake of simplicity, however, the above formula only includes the main constituents of the crystal lattice (Al, Ga, In, N), even though these constituents may be partially replaced by small quantities of further substances.
Epitaxy processes are usually used to produce semiconductor components based on nitride compound semiconductors. Since a reduction in the defect density in the nitride compound semiconductor is one of the main preconditions for increasing the internal efficiency of optoelectronic semiconductor chips based on nitride compound semiconductors, it is desirable to use a growth substrate which, like the layer sequence which is to be epitaxially grown, is formed from a nitride compound semiconductor. However, substrates made from a nitride compound semiconductor, in particular GaN, can only be produced at high technical cost and are therefore considerably more expensive than the alternative substrates made from SiC and sapphire which are customarily used.
A known process for producing optoelectronic components based on nitride compound semiconductors is based on what is known as thin-film technology. In this technology, a functional semiconductor layer sequence is first of all grown epitaxially on a growth substrate, then a new handle is applied to the opposite surface of the semiconductor layer sequence from the growth substrate, and then the growth substrate is detached. This has the advantage in particular that the growth substrate can be reused. The detaching of a sapphire growth substrate from a semiconductor layer sequence comprising a nitride compound semiconductor can be carried out, for example using a laser lift-off method which is known from U.S. Pat. No. 6,559,075. However, this process cannot readily be applied to substrates made from a nitride compound semiconductor.